Formulae and Their Uses


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A formula consists of constants and variables.

In a formula the variables are interrelated. A formula is an equation that establishes a relationship among the variables involved in it. The plural form of formula is formulae.

Framing a formula:

Expressing a given statement in the form of an equation by using variables and mathematical symbols is called framing a formula.

Subject of a formula:

The subject of a formula is a variable that is expressed in terms of the other variables.

In other words, in a formula, the variable standing alone on one side of the equality sign is called the subject of the formula. The subject of a formula always lies on left hand side of the equality sign. The coefficient of the subject is always one. The subject of a formula does not link with any other quantities.

Changing the subject of a formula:

Any one variable of a formula can be made the subject by transferring the variables.

Evaluation of the subject of a formula (substitution method):

Finding the value of the subject by substituting the values of the other variables is called the evaluation of the subject of a formula.

Steps to evaluate the subject of a formula:

  • Make the required variable the subject.

  • Substitute the values of the other variables in the formula.

  • Simplify the formula.

1 . what is formula give some example

formula is estabilshing the relation among varabiles and constant involve in it
i think so.....

2 . Find the present ages of the father and his son.

nice question its easy so try to do it your self, i got the answer but you can do it your self easily

3 . What is the income of Ramesh?

Let the income of Ramesh be Rs x.
Part of the income given to son = x/3
Part of the income given to daughter =...

4 . H=2/5nd2 .Find d, when H=1620and n=18


5 . What are the lenghts of the sides of the rectangle?

Let the breadth of the rectanle be 'x' cm
Length of the rectangle = (x + 20) cm
Perimeter of the rectagle...